This is an estimate of the amount of a substance in food that can be ingested daily over a lifetime by humans without appreciable health risk. The concept of the ADI has been developed principally by WHO and FAO and is relevant to chemicals such as additives to foods, residues of pesticides and veterinary drugs in foods. ADIs are derived from laboratory toxicity data, and from human experiences of such chemicals when this is available, and incorporate a safety factor. The ADI is thus an estimate of the amount of a substance in food that can be ingested over a lifetime by humans without significant risk to health (for contaminants in food and drinking water, tolerable intakes - daily or weekly - are used). See tolerable daily intake.